Self-powered locks have been known for some time. Self-powered locks are generally of two types. In the first type, movement of a member such as a knob or a handle provides power to the lock. Entry of the combination is accomplished by, for example, a key or card carrying a code or another code input device. The generation of power is separate from the code entry device.
The other type of such self-powered lock is exemplified by the lock disclosed in U.S. Pat. No. 5,061,923 issued to Miller et al., the disclosure of which is incorporated by reference herein in its entirety. In this type of lock, the same mechanism is used for generation of power for the lock and for the creation of electronic pulses. This type of lock has a permanently engaged drive from a dial to a stepper motor, which outputs voltage pulses in both directions of rotation and provides the same pulses to the microprocessor for purposes of controlling the lock, and in some configurations, for entering the combination.
In general, it is necessary to maintain the desired combination(s) within electronics interior to a safe container, behind a secured door, or in another inaccessible location. The number and status display, by necessity, must be located on the exterior and accessible to the operator of the lock. This has caused self-powered locks to be designed with electrical conductors connected between the outside electronics and the power generation device, which is generally located with the interior electronics. This connection method has proven cost effective in the past, but has caused some challenges during installation and some issues with reliability if the electrical conductors between the interior and exterior electronics become twisted or separated from the interior or exterior electronics.